This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. The Ebola virus glycoproteins, sGP and GP, are major determinants of the virus's pathogenicity. sGP and GP are encoded by the same gene, and thus share 295 amino acids of N-terminal sequence. However, a transcriptional editing event causes them to have different C-terminal sequences. The different C termini result in unique patterns of disulfide bonding, different structures, and different roles in pathogenesis. sGP forms an antiparallel dimer and is secreted in large quantities from infected cells. GP forms a parallel trimer on the viral surface, and functions in viral attachment, fusion, and tropism. Comparative structural analysis of sGP and GP should explain how two structures arise from the same sequence, and provide templates to guide the design of vaccines that elicit antibodies which target the virus rather than the secreted proteins.